The present invention is directed toward a method of making a novel, lightweight firing container using fused alumina bubbles. The present invention also relates to lightweight firing containers manufactured with fused alumina bubbles.
Firing containers are used for holding parts that require firing. The weight of conventional firing containers is high compared to the amount of material they hold. For instance, one size of firing containers weighs about 22.5 pounds and holds only approximately 5 pounds of material.
The general procedure for firing begins with loading the firing containers with parts that need to be fired. Loaded firing containers are then placed on kiln cars and fired to temperatures up to approximately 3200 degrees Fahrenheit. After the firing is complete, and the loaded firing containers have cooled to a temperature suitable for handling, the firing containers are removed from the kiln cars and the fired products are dumped from the containers. The firing containers are then reloaded and the entire process is repeated. These firing containers are stacked on kiln cars in such a manner that the operator must either lift the filled containers to a position over his head or reach across a distance to set them on a stack.
Because the firing containers are heavy, the lifting and stacking can result in fatigue or injury to the operator. It is, therefore, desirable to decrease the weight of the firing containers so that the operator experiences less stress on his body and is less likely to injure himself.
The reduction in the weight of the firing containers, however, cannot greatly reduce the performance of the container. The performance of a firing container is based on the ability of the container both to withstand repeated heating and cooling cycles without excessive cracking and to retain its dimensional integrity. The bottom of the firing container must not warp to such a degree that the container becomes unusable. A need, therefore, exists for a lightweight firing container that is able to survive the repeated heating and cooling cycles without cracking or warping.